Shielding system and method for an entertainment system for use with a magnetic resonance imaging device

ABSTRACT

An entertainment system for use with a magnetic resonance imaging (MRI) device has a display panel and associated electronics which are mounted close to the MRI device and which are enclosed within a Faraday shield. A patient may be placed within the MRI device in a variety of positions and may view images from the display panel either directly or through a mirror, prism, or corner reflector. In order for the patient to view the images in the correct orientation regardless of the exact positioning, the display panel can display the images normally, with the images flipped from top to bottom, with the images flipped from left to right, and with the images flipped both from top to bottom and from left to right. The display panel is formed with a dark-colored focus area which forms a border around the display panel and which directs the attention of the patient toward the images on the display panel. The entertainment system indicates the various states of the MRI procedure through a set of lamps colored and arranged to simulate a typical traffic light. By using the traffic light configuration and coloring, patients can easily determine the state of the MRI procedure. The entertainment system calms the patient, distracts the patient from the MRI procedure, and makes it easier for the patient to remain still during the MRI procedure. As a result of the entertainment system, better quality images may be obtained with the MRI device.

The present application is a continuation application of co-pendingapplication entitled "Entertainment System for Use with a MagneticResonance Imaging Device", filed on Aug. 14, 1995 and assigned Ser. No.08/514,849.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an entertainment system andmethod and, more particularly, to an entertainment system and method foruse with a magnetic resonance imaging device.

2. Description of the Prior Art

In the medical field, magnetic resonance imaging (MRI) is a commonlyused non-invasive technique to diagnose the medical condition of apatient. Typically, the patient is placed within a large homogeneousmagnetic field and is subjected to a set of gradient fields and RFfields. The various fields are accurately controlled to cause nucleiwithin a selected slice of the patient to precess about an axis and toemit RF signals. These signals are then used to reconstruct an image ofthe slice. By varying the gradient fields, images of the patient atdifferent slices may be captured. The separate slices can then becombined to form a complete scan of the patient.

A typical MRI device is designed to have a central bore within which thepatient is inserted. This bore is fairly small and may induceclaustrophobic feelings in the patient. As is known in the art, theseclaustrophobic feelings may be reduced or eliminated by providing thepatient with some type of entertainment.

A problem with providing the patient with some type of entertainment isthat very small magnetic fields generated by another device can destroythe images generated by the MRI device. Conversely, the strong fieldsgenerated by the MRI device may prevent the normal operation of certaindevices, such as a cathode ray tube (CRT) or liquid display panel (LCD),within the vicinity of the MRI device. Therefore, any type of systemused to entertain the patient must not generate any stray magneticfields in the vicinity of the MRI device and should be shielded from themagnetic fields generated by the MRI device.

Despite these constraints, many types of systems have been designed toprovide the patient with some entertainment thereby distracting thepatient from the MRI procedure. In order to isolate the entertainmentsystems from the fields generated by the MRI device and to prevent anymagnetic fields from effecting the MRI device, some systems pipe invideo images to the patient while the patient is within the MRI device.For instance, U.S. Pat. No. 4,901,141 to Costello and U.S. Pat. No.5,134,373 to Tsuruno et al. both disclose video systems in which videoimages are supplied through optic fibers to the patient. These systemsare rather expensive to install since the MRI device must beretro-fitted with the optical fibers.

Rather than routing the video images by optical fiber, another type ofentertainment system generates an image behind the MRI device and has amirror for reflecting the image to the patient. For instance, a viewingsystem in U.S. Pat. No. 5,076,275 to Bechor et al. and an MRI videosystem disclosed in a Nuclear Associates brochure both reflect imagesgenerated from a display panel located behind the patient into the eyesof the patient. These systems may use a reflective surface mounted tothe MRI device or reflective surfaces which are mounted onto gogglesworn by the patient.

While these systems are easier to install than systems which route thevideo images through optical fibers, these systems do not readilyaccommodate different positions of the patient. For instance, while apatient is often in a supine position, the MRI procedures vary inwhether the patient is placed in a supine position or prone position orwhether the patient is placed head-first or feet-first within the MRIdevice. The conventional entertainment systems cannot accommodate all ofthe different positions that a patient may be placed and, at most, maybe able to accommodate only a single position of the patient. It istherefore a problem with conventional entertainment systems which areused with MRI devices to provide video images to the patient for avariety of positions.

Also, with many of the existing MRI entertainment systems, the patientmay find it difficult to focus on the video images and may thereforefind it difficult to completely relax. This may be especially true forthe entertainment systems which reflect the video images from behind theMRI device to the patient. With this type of entertainment system, thepatient may be distracted by items which are adjacent to the displayscreen or by people working behind the patient. It would therefore bedesirable to have the patient focus on the video images during the MRIprocedure so that the patient is able to relax.

In order for the MRI device to produce high resolution images of thepatient, the patient must remain as still as possible while the MRIdevice is operating. While the entire procedure may last more than anhour in duration, the MRI device is not imaging during the entire hour.Instead, the procedure is usually comprised of two or more imagingsequences with pauses in between the sequences. During these pausesbetween sequences, the patient can relax and may move about a minimalamount.

The status of the MRI procedure, such as when the MRI device is imagingor pausing, may be indicated to the patient in a variety of ways. Onemanner of indicating the states of the MRI procedure is by simplyverbally informing the patient of whether the MRI device is imaging,pausing, or about to image. A better way, disclosed in JP-A-145643, isto flash a colored light to warn the patient that an imaging sequence isabout to begin and to steadily illuminate the MRI device with thecolored light for the period during which the MRI device is imaging.

A still better way, disclosed in U.S. Pat. No. 5,355,885 to Tsuda etal., provides the patient with information about the particularoperation that is occurring. With the system disclosed by Tsuda et al.,the inspection space within the MRI device is illuminated with a numberof colors to indicate the different operations. This system illuminatesthe inspection space with a mixture of green and yellow light and thenilluminates the space with just a yellow light during a pretreatmentperiod. A red light flashes before the beginning of an imaging sequenceand then the green light illuminates the space during the imagingsequence. As the imaging sequence progresses, the space is illuminatedwith a mixture of both green and yellow lights with the mixture slowlychanging to entirely yellow to indicate the end of the imaging sequence.As with the beginning of the MRI procedure, the end of the entireprocedure is indicated with the mixture of green and yellow lights.

While the system disclosed in Tsuda et al. can indicate the variousstates of the MRI device, it may be difficult for many patients todetermine the exact state of the MRI device. The patient may be in astate of anxiety and may not remember the exact relationship between thecolors and the states of the MRI device. Also, many patients may havetrouble distinguishing a slight mixture of colors, such as green andyellow, from a pure color of light, such as just yellow. Consequently,some patients may determine that the MRI device is pausing when in factthe MRI device is still acquiring images. It is therefore a problem toaccurately and reliably indicate the various states of the MRI procedureto a patient.

SUMMARY OF THE INVENTION

An object of the present invention is to reliably and accuratelyindicate the various states of an MRI procedure to a patient.

Another object of the present invention is to calm a patient byproviding video images during an MRI procedure.

Another object of the present invention is to provide a low cost systemfor entertaining a patient.

Another object of the present invention is to provide video images to apatient for a number of different positions in which the patient may beplaced within an MRI device.

Additional objects, advantages, and novel features of the invention willbe set forth in the description which follows, and will become apparentto those skilled in the art upon reading this description or practicingthe invention.

To achieve the foregoing and other objects, a novel entertainment systemfor use with a magnetic resonance imaging (MRI) device receives videodata and has a mode selector for placing the entertainment system intoany one of a plurality of modes. A data processor alters the sequence ofthe video data according to the mode selected, with each mode associatedwith a different sequence of data. A display panel generates a videoimage based on the sequence of video data supplied from the dataprocessor with the orientation of the video image on the display panelbeing different for each of the different modes. The mode of theentertainment system is selected according to the position of a patientwithin the MRI device so that the video image will appear to be in itsnormal orientation from the patient's viewing position.

In the preferred embodiment, the patient may be positioned head-first orfeet-first within the MRI device and may be in a supine or proneposition. Additionally, the video image may be reflected off of amirror, prism, or corner reflector before reaching the eyes of thepatient. To accommodate these different viewing positions, theentertainment system has the different modes in which the image may beunaltered, may be flipped from top to bottom, may be flipped from leftto right, or may be flipped both from top to bottom and from left toright.

An entertainment system, according to a second aspect of the invention,receives video data, such as from a TV, cable TV, VCR, etc., and has adisplay panel for generating a digital image. A focus area is formedcompletely around the display panel and has a surface area greater thanthe surface area of the display panel. The focus area has a dark colorand helps to direct a gaze of a patient within the MRI device to thevideo image on the display panel. By focusing the attention of thepatient onto the display panel, the patient becomes distracted, relaxed,and is better able to remain still during an imaging sequence. Since thepatient is better able to remain still, the entertainment system of theinvention can improve the quality of images acquired by the MRI device.

In a third aspect, the invention relates to a system for indicating thevarious states of an MRI device to a patient. The indicating systemcomprises a red lamp, a yellow lamp, and a green lamp arranged in atraffic light configuration so that the yellow lamp is located directlybeneath the red lamp and the green lamp is located directly beneath theyellow lamp. The system further has first, second, and third drivingcircuits for respectively driving the red, yellow, and green lamps. Thefirst, second, and third driving circuits are activated in accordancewith an imaging sequence of the MRI device so that the green lamp isactivated when the MRI device is inactive, the red lamp is activatedwhen the MRI device is acquiring images of the patient, and the yellowlamp is activated before the MRI device begins to acquire the images ofthe patient and is activated for a predetermined period of time. Thetraffic light configuration of the red, yellow, and green lamps permitsthe patient to easily determine the states of the MRI device even whenthe patient is in a state of anxiety or has feelings of claustrophobia.

In a fourth aspect, the invention relates to a method of providingimages to a patient during a magnetic resonance imaging procedure. Themethod comprises the steps of receiving video data at an input terminalof an entertainment system and placing the entertainment system into oneof a plurality of modes. The sequence of the digital video data iscontrolled based upon the selected mode, with each mode associated witha unique sequence of digital video data. A video image is generated on adisplay panel based on the controlled sequence of digital video data.The mode of the entertainment system is selected based on a position ofthe patient within the MRI device so that the patient can view the videoimage in its normal orientation.

In a fifth aspect, the invention relates to a method for indicating thevarious states of an MRI device to a patient. The method comprises thesteps of arranging a red lamp, a yellow lamp, and a green lamp in atraffic light configuration with the yellow lamp located directlybeneath the red lamp and the green lamp located directly beneath theyellow lamp. The green lamp is activated when the MRI device isinactive, the red lamp is activated when the MRI device is acquiringimages of the patient, and the yellow lamp is activated before the MRIdevice begins to acquire images of the patient and is activated for apredetermined period of time. The arrangement of the red lamp, yellow,and green lamps in the traffic light configuration permits the patientto easily determine the states of the MRI device.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in, and form a partof, the specification, illustrate a preferred embodiment of the presentinvention and, together with the description, serve to explain theprinciples of the invention. The drawings are not necessarily to scale,emphasis instead being placed upon clearly illustrating the principlesof the invention. In the drawings:

FIG. 1 is a side view of a patient within an MRI device having anentertainment system according to a preferred embodiment of theinvention;

FIG. 2 is a perspective view of a stand for holding a display panelforming part of the entertainment system of the invention;

FIG. 3 is a block diagram of the entertainment system according to apreferred embodiment;

FIG. 4 is a top view of an exemplary remote control unit shown in FIG.3;

FIGS. 5A and 5B are block diagrams of a video processing circuit andindicator processing circuit shown in the entertainment system of FIG.3; and

FIG. 6 is an exploded view of a shielding enclosure and display panel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiment of theinvention. With reference to FIG. 1, an entertainment system accordingto the invention is shown with a magnetic resonance imaging (MRI) devicein which a patient P is placed upon a moveable bed 12. An image or setof images are generated by a display panel 20 and may be reflected offof a mirror, prism, or corner reflector 14 into the eyes of the patientP. As is known in the industry, these images can distract the patient Pfrom the MRI procedure and help the patient P to relax. By distractingand relaxing the patient P, the patient P is able to remain still forlonger periods of time, which permits the MRI device to obtain betterquality images.

The display panel 20 may be positioned relative to the MRI device in anumber of different ways, such as mounting the display panel 20 directlyonto a wall behind or in front of the MRI device or incorporating thedisplay panel 20 within a stand, such as stand 22 shown in FIG. 2. Thestand 22 has a base 24, a vertical extension member 26, and a shieldingenclosure 28 for housing the display panel 20. While not shown, thevertical extension member 26 is adjustable so that the display panel 20may be placed at different heights.

The preferred distance for placing the display panel 20 and stand 22relative to the MRI device will depend upon a number of factors,including the size of the display panel 20. In the example disclosed,the display panel 20 has a diagonal length of 10.4 inches and is placedat any suitable distance to the MRI device, typically in the range ofabout 3 to 5 feet from the MRI device. It should be understood that thedisplay panel 20 may have a different size and that the display panel 20may be placed at other distances from the rear of the MRI device.

The display panel 20 preferably has a number of indicator lamps 23 forindicating the various states of the MRI procedure. The lamps 23 arecomprised of a red lamp 23R, a yellow lamp 23Y, and a green lamp 23Garranged along a vertical column. The lamps 23 are energized so that thegreen lamp 23G is lit to indicate that the MRI device is inactive, theyellow lamp 23Y is lit to indicate that an imaging sequence is about tobegin, and the red lamp 23R is lit to indicate that the MRI device isacquiring images of the patient P.

The colors of the lamps 23 and the arrangement of the lamps 23 arespecifically designed to simulate the appearance and operation of atypical traffic light. When the green lamp 23G is lit, the patient Pknows that the MRI device is inactive and that he or she is able to "go"or move to different locations. On the other hand, when the red lamp 23Ris lit, the patient P knows that the MRI device is acquiring images andthat he or she must "stop" all motion and remain as still as possible.The yellow lamp 23Y, similar to the traffic light, warns the patient Pthat he or she will soon have to "stop" all motion.

The traffic light configuration and selection of colors for the lamps 23clearly and simply indicate the various states of the MRI device to thepatient P. Most patients P, even those who may be too young to drive,understand that green means go, that red means stop, and that yellow isa warning light. Most patients P can therefore easily determine whetherhe or she can move about based upon the signals from the lamps 23. Thus,even when a patient P is in a heightened state of anxiety or hasfeelings of claustrophobia, the patient P should still be able todetermine the states of the MRI device.

In addition to the lamps 23 and the display panel 20, the shieldingenclosure 28 also has a focus area 29. The focus area 29 forms a bordercompletely around the perimeter of the display panel 20 and comprises asubstantial portion of the front surface of the shielding enclosure 28.By placing the display panel 20 within a large focus area 29, the gazefrom a patient P is directed toward the center of the focus area 29 andonto the display panel 20. Thus, the focus area 29 directs the attentionof the patient P toward the images generated by the display panel 20.

The focus area 29, in addition to having a proportionately large amountof surface area on the face of the shielding enclosure 28, is alsoselected to have a dark color, preferably black. A dark focus area 29increases the amount of contrast between itself and the images on thedisplay panel 20 and, consequently, further directs the gaze from thepatient P onto the display panel 20. An overall effect of the focus area29 is to direct the patient's P attention to the video image therebyrelaxing the patient P and relieving feelings of anxiety orclaustrophobia. Thus, with the focus area 29, the patient P can moreeasily remain still during the MRI procedure.

A block diagram of the entertainment system is shown in FIG. 3. Theentertainment system comprises at least one video or audio/video device30 for producing video signals that are sent to a video processingcircuit 60. When the video device 30 is an audio/video device 30, theaudio signals from the device 30 are supplied to an audio selector 34.The invention may use any type of video or audio/video device 30. Thus,for example, the device 30 may be a laser disc player, a video cassetterecorder (VCR), or an output from a cable television system.

The entertainment system may additionally have at least one audio device32 which supplies its audio signals to the audio selector 34. The audioselector 34 passes only one of the audio signals supplied at its inputsto an acoustical transducer 36 which converts the signals into sound.

The invention is not limited to any specific type of audio device 32,audio selector 34, or acoustical transducer 36 and any suitablecomponents may be used. For instance, the audio device 32, audioselector 34 and acoustical transducer 36 may be those disclosed in U.S.Pat. No. 5,076,275 to Bechor et al., the disclosure of which isincorporated by reference. The audio device 32 may comprise a tape deck,CD player, or tuner and the audio selector 34 may be a separate device,such as a simple switch, or may be incorporated within another audiodevice 32, such as the tuner. The acoustical transducer 36 may comprisea loudspeaker and/or may comprise a headphone operable within the boreof the MRI device.

The video processing circuit 60 can drive the display panel 20 in anyone of four modes which are selected according to the position of thepatient P within the MRI device. In a first mode, when the patient P ishead-first within the MRI device and is in a prone position, the videoprocessing circuit 60 drives the display panel 20 in a normal viewingformat so that the images from the display panel 20 may be directlyviewed by the patient P without any mirror 14. In other words, when thepatient P looks at the display panel 20 directly, the images from thedisplay panel 20 are positioned normally both from left to right andfrom top to bottom.

The video processing circuit 60 drives the display panel 20 in a secondmode when the patient P is head-first within the MRI device, is in asupine position, and receives the video images from the mirror 14. Whenthe patient P is in this position, the video processing circuit 60drives the display panel 20 so that the images are flipped from left toright.

In a third mode, the patient P is head-first within the MRI device, issupine, and views images from the display panel 20 without the mirror14. In order for the patient P to view the image in their correctorientation, the video processing circuit 60 drives the display panel 20so that the images are flipped from top to bottom.

Finally, when the patient P is feet-first within the MRI device, is in asupine position, and views the images from the display panel 20 with themirror 14, which is the position shown in FIG. 1(A), the videoprocessing circuit 60 drives the display panel 20 in a fourth mode. Inthis mode, the images from the display panel are flipped from top tobottom and are flipped from left to right. Thus, when the patient Pviews these images through the mirror, the images from the display panel20 will appear in their normal orientation.

The entertainment system also comprises a remote control unit 38 whichsends signals to both an indicator processing circuit 50 and to thevideo processing circuit 60. With reference to FIG. 4, in the preferredembodiment the remote control unit 38 comprises a manually activatedunit having two buttons 41a and 41b, four indicators 42 for videoprocessing, and one indicator 43 for indicator or status processor. Thebutton 41b is depressed by an MRI operator before the beginning of animaging sequence. The indicator processor circuit 50 lights the yellowlamp 23Y for a predetermined period of time and then lights the red lamp23R to indicate that all motion must "stop". At the end of the imagingsequence, the MRI operator presses the button 41b again to cause theindicator processor circuit 50 to light the green lamp 23G to indicatethat the patient P is free to move about.

The other button 41a is associated with four video indicators 42 and isfor placing the display panel 20 in one of the four display modes. TheMRI operator therefore only needs to depress the button 41a and togglethrough until the indicator 42 lit corresponds to the position of thepatient P in order for the images from the display panel 20 to beorientated correctly relative to the patient P. Preferably, theindicators 42 are light emitting diodes (LED) to indicate the fourorientations and the LED associated with a selected orientation isenergized in order to indicate the selected mode. Rather than manuallydepressing the buttons 41, both the indicator processing signals andorientation mode signal can be automatically produced by the MRIcomputer system and sent over a serial link, through an MRI computerinterface 44, and to the indicator processing circuit 50 and the videoprocessing circuit 60.

FIGS. 5A and 5B depict an example of the indicator processing circuit 50and the video processing circuit 60. The video processing circuit 60 canreceive video signals in a number of different formats and receives thevideo signals at either terminal 61a or 61b, depending upon theparticular format of the video signal. If the video device 30 outputssignals as separate chroma C and luminance Y signals, the chroma C andluminance Y signals are input at terminal 61a and are respectivelyrouted to a chroma analog-to-digital (A/D) converter 62 and to aluminance input at a luminance/composite A/D converter 64. If the videodevice 30 instead outputs signals as a composite video signal, then thiscomposite video signal is routed to a composite input at theluminance/composite A/D converter 64.

The digital outputs from the chroma A/D converter 62 and theluminance/composite A/D converter 64 are supplied to a multi-standarddecoder 66. The multi-standard decoder 66 determines the type of videosignal that is being input to the video processing circuit 60 andpreferably determines whether the video signals are in the NTSC format,the PAL format, or the SECAM format. The multi-standard decoder 66reformats the chroma and luminance data and outputs the video data in aY, U, and V data format. The Y, U, and V data from the multi-standarddecoder 66 is input to a color space converter 68 which separates thedata into red R, green G, and blue B digital data.

The red R, green G, and blue B digital data are output from the colorspace converter 68 and are input into a line doubling circuit 70. Thedisplay panel 20 is preferably an LCD panel having 480 rows of pixels.Since the video signals only have about 240 lines of data, the linedoubling circuit 70 must double the number of lines in order for thesignals to be formatted for the LCD panel 20. The video signals arrivein an interlaced format with the data for even lines being alternatedwith the data for the odd lines. The line doubling circuit 70 convertsthe interlaced data format into a progressive scan format compatiblewith the LCD panel 20 by doubling both the data for the even lines andthe data for the odd lines and alternately supplying the even and odddata to a data multiplexer 72.

In addition to receiving the doubled line data from the line doublingcircuit 70, the data multiplexer 72 also receives another input frommemory 74. The memory 74 stores an image or a number of images which maybe displayed on the display panel 20. For instance, the memory 74 maystore a logo or banner for Health Images or may be a logo customdesigned for the particular office operating the MRI device. The imagesfrom the memory 74 are routed through the data multiplexer 72 andultimately to the display panel 20 only when the video processingcircuit 60 is not receiving any video signals from the video device 30.Thus, the signals from the video device 30 take precedent over theimages stored in memory 74.

A microprocessor 76 controls the data multiplexer 72 so that the imagesfrom the memory 74 are displayed only when the video device 30 isinactive. While not shown, the microprocessor 76 has access to memoryincluding, but not limited to, RAM, ROM for storing software, and a harddrive. The microprocessor 76 is informed by the multi-standard decoder66 whether video signals are being input from a video device 30. Thus,when video signals are not being input to the multi-standard decoder 66,the microprocessor 76 will control the data multiplexer 72 so that itoutputs the video image stored in memory 74.

A framestore 78 receives the output from the data multiplexer 72 and hasan output which drives the LCD panel 20. The framestore 78 is comprisedof a block of video RAM which temporarily stores the video data beforebeing displayed on the display panel 20. The framestore 78 can changethe order of the video data so that the display panel 20 projects avideo image in any one of the four modes. To control the sequence of thevideo data, the framestore 78 has a control input FLIP IMAGE forflipping the image from top to bottom and a REAR PROJECT control inputfor rotating the image from left to right.

The framestore 78 may be conceptualized as an array of data spaces.Without any control signals, the framestore 78 will store lines of datafrom the top to the bottom of the data array and from the left to theright of the data array. When the framestore 78 receives a controlsignal on the FLIP IMAGE input, the lines of the video data input to theframestore 78 will instead be stored in a sequence from the bottom tothe top of the data array. If the framestore 78 receives a controlsignal on the REAR PROJECT input, then the video data within each linewill be stored from right to left of the data array. Since the videodata is always output from the framestore 78 from the top to bottom ofthe data array and from the left to right of the array, the video datawill appear to have been flipped from top to bottom if the FLIP IMAGEinput was received and will appear to have been rotated from left toright if the REAR PROJECT input was received.

The multi-standard decoder 66 separates the horizontal sync signal fromthe received video signals and supplies the horizontal sync signal tocertain components of the video processing circuit 60, such as the linedoubling circuit 70 and horizontal sync generator 82. The horizontalsync generator 82 doubles the speed of the horizontal sync signal andoutputs this doubled signal to an image positioning circuit 84.

The image positioning circuit 84 permits both horizontal and verticalpositional adjustments of an image on the LCD panel 20. The imagepositioning circuit 84 receives the doubled horizontal sync signal fromthe horizontal sync generator 82 and adjusts the timing of the doublehorizontal sync signal to cause a corresponding adjustment in thehorizontal position of the image on the display panel 20. Similarly, theimage positioning circuit 84 receives a vertical sync signal from themulti-standard decoder 66 and adjusts the timing of this signal to causea corresponding adjustment in the vertical position of the image on thedisplay panel 20.

A control decode 80 receives information from the microprocessor 76 andcontrols a number of devices according to the information received. Theinformation received from the microprocessor 76 includes information asto which one of the four modes the display panel 20 should be placed.After receiving this information, the control decode 80 will sendappropriate control signals to the FLIP IMAGE and REAR PROJECT inputs onthe framestore 78.

The microprocessor 76 also sends the control decode 80 values of thehorizontal and vertical adjustments. The values of the horizontal andvertical adjustments of the image depend upon the type of video signal,such as PAL or NTSC, and are stored in memory accessible by themicroprocessor 76. The microprocessor 76 is informed of the type ofvideo signal by the multi-standard decoder 66 and then sends theappropriate values of the adjustments to the control decode 80, whichrelays the information to the image positioning circuit 84 for executingthe positional adjustments.

The control decode 80 also receives information from the remote controlunit 38. After a button has been pressed on the remote control unit 38,the control decode 80 relays the information as to which button has beenpressed to the microprocessor 76. If one of the buttons for controllingthe mode of displaying the video was depressed, then the microprocessor76 sends signals through the control decode 80 to the remote controlunit 38 for energizing the LED associated with the depressed button sothat the selected mode is indicated to the MRI operator.

Through the control decode 80, the microprocessor 76 also controls thelamps 23 to indicate the present state of the MRI procedure. After themicroprocessor 76 receives an indication from the control decode 80 thatthe button for the lamps 23 on the remote control unit 38 has beendepressed, the microprocessor 76 commands the control decode 80 toactivate the yellow lamp 23Y to warn the patient that an imagingprocedure is about to begin. After the microprocessor 76 detects that apredetermined period of time has elapsed, the microprocessor 76 commandsthe control decode 80 to activate the red lamp 23R. At the completion ofthe imaging sequence, when the microprocessor 76 receives an indicationthrough the control decode 80 that the button on the remote control unit38 has been depressed again, the microprocessor 76 commands the controldecode 80 to activate the green lamp 23G to let the patient P know thathe or she is allowed to move.

In response to a command from the microprocessor 76, the control decode80 sends an appropriate control signal to a set of panel lamp drivers86. The set of panel lamp drivers 86 comprises first, second, and thirddrivers for the red, yellow, and green lamps 23, respectively. The panellamp drivers 86 convert the digital 5 volt signal from the controldecode 80 into a 12 volt power signal suitable for driving the 12 voltlamps 23.

Instead of or in addition to the remote control unit 38, theentertainment system may have a wireless remote control unit 87. Thewireless remote control unit 87 transmits infrared signals to an IRcircuit 88 which converts the optical signals into electrical signalsand outputs digital data signals to the microprocessor 76. The wirelessremote control unit 38 may have the same buttons which are on the remotecontrol unit 38 and/or may have other buttons for controlling otheraspects of the entertainment system.

A serial port interface 90 permits serial communication with themicroprocessor 76. The serial port interface 90 may be used as adiagnostic tool to debug existing software or may be used to reprogramthe microprocessor 76. The microprocessor 76 could also use the serialport interface 90 to receive serial commands from another device. Forinstance, the microprocessor 76 may be informed by the MRI device ofwhen an imaging sequence is about to begin or when the sequence hasended. The microprocessor 76 could then automatically generate signalsto the indicator processing circuit 50 and to the video processingcircuit 60 without any operator intervention. With such a control unit,the MRI operator would not have to place the display panel 20 in theseparate display modes and would not have to depress a button at thebeginning or end of each imaging sequence.

The data multiplexer 72, the control decode 80, the horizontal syncgenerator 82, and the image positioning circuit 84 form part of a fieldprogrammable gate array (FPGA). The programming of the FPGA will beapparent from the above descriptions of the data multiplexer 72, controldecode 80, horizontal sync generator 82, and image positioning circuit84 and, accordingly, will not be described in any further detail.

As discussed above, the display panel 20 must be shielded from themagnetic fields generated by the MRI device and the MRI device must beshielded from the magnetic fields generated by the display panel 20 andassociated electronics. To accomplish this shielding, with reference toFIG. 6, the shielding enclosure 28 comprises a metal box 32, a metalcover plate 34 having the focus area 29, an RFI gasket 36, and a screen38.

The display panel 20, red lamp 23R, yellow lamp 23Y, green lamp 23G, andother electronics are mounted within the metal box 32. The metal coverplate 34 has a cut-out portion covered with the mesh or screen 38 ofthin copper wires. The wires forming the copper mesh 38 are thin enoughso that the images from the display panel 20 are not obstructed butrather are clearly visible by the patient P. The lamps 23R, 23Y, and 23Gare also covered by copper mesh mounted to the cover plate 34 with brassrings 37.

The cover plate 34 is mounted to the front of the metal box 32 with theRFI gasket 36 placed therebetween. The RFI gasket, the metal box 32, thecover plate 33, and the copper mesh 38 form a Faraday shield tocompletely shield the MRI device from any fields generated by thedisplay panel 20, lamps 23, and other electronics and to shield thecomponents within the enclosure 28 from the fields generated by the MRIdevice. A magnetic shield 39 may be used to house components which areespecially sensitive to strong magnetic fields.

The foregoing description of the preferred embodiment of the inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed. Many modifications and variations are possible in lightof the above teaching.

For example, while the invention has been described in conjunction withan MRI device, the invention may be used with other equipment or inother environments, such as in a dental office or with out-patientsurgery. Further, an intercom system may be incorporated with the audioportion of the entertainment system to provide a channel ofcommunication between the patient P and the MRI operator. Further, theremote control unit 38 may have a greater or lesser number of buttons.

Also, when the MRI computer interface 44 is used, additional features oritems may be displayed on the display panel 20. For instance, the MRIcomputer interface 44 may receive data indicating the amount of timeremaining in the MRI procedure. The amount of time may be displayed onthe display panel 20 as a 100% bar graph which is reduced in size and inrate according to the percentage of time which has elapsed. When the MRIprocedure is completed, the bar graph is reduced to zero and the greenlamp 23G is lit. Alternatively, the amount of time remaining may beindicated in minutes and seconds on the display panel 20 and will countdown to zero at which time the green lamp 23G will be lit. With eitheralternative, the display of time will have the same orientation as thevideo image whereby the remaining time can always be correctly viewed bythe patient P. The two alternatives may be user selectable, such as bydepressing another button on the remote control unit 38.

It should be understood that the display panel 20 can project imageswhich are not intended to merely entertain the patient P. For example,the display panel 20 may have commercial advertisements instead of or inaddition to images displayed on the panel 20 intended to distract andentertain the patient P. Further, the display panel 20 may be used instudies of brain activity which require visual stimulus, such as animage, a message to be read, or a problem to be solved. The displaypanel 20 therefore permits the "functional imaging" of a patient P.

The embodiment was chosen and described in order to explain theprinciples of the invention and their practical application to therebyenable others skilled in the art to utilize the invention and variousembodiments and with various modifications as are best suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the claims.

Wherefore, the following is claimed:
 1. An arrangement for entertaininga patient within a magnetic resonance imaging device, comprising:amagnetic resonance imaging device in an examination room; a patientpositioned within said magnetic resonance imaging device; a videodisplay panel having a video display screen, said video display panelbeing positioned in said examination room within a magnetic fieldgenerated by said magnetic resonance imaging device, said patient beingcapable of direct viewing of said video display screen; an imagegenerated on said display screen to entertain said patient; a mirrordisposed within said magnetic resonance imaging device, said patientbeing capable of viewing a direct reflection of said display screen insaid mirror without fiber optic coupling; and a magnetically shieldedenclosure integral to said video display panel, said enclosure shieldingsaid magnetic resonance imaging device from an internal magnetic fieldgenerated in said video display panel, and said enclosure shielding saidvideo display from an external magnetic field generated by said magneticresonance imaging device, said magnetically shielded enclosure having ametal box with an open face, a cover plate with a cut-out for the videodisplay screen, said cover plate fastened to said metal box, a radiofrequency interference gasket to seal the joint said metal box and saidcover plate, and a wire mesh covering said cut-out in said plate.
 2. Thearrangement of claim 1, wherein said image generated on said displayscreen is displayed in a normal viewing orientation when said patient isin a headfirst, prone position for direct viewing by said patient, saidimage being reversed from left to right when said patient is in ahead-first supine position viewing a reflection of said display screenon said mirror, said image being reversed from top to bottom when saidpatient is in a head-first supine position for direct viewing by saidpatient, and said image being reversed from left to right and from topto bottom when said patient is in a feet-first supine position viewing areflection of said display screen on said mirror.
 3. The arrangement ofclaim 1, wherein said cover plate further comprises at least one holefor a viewing lamp, said hole covered by a second wire mesh mounted tosaid cover plate with a brass ring, said wire mesh constructed from thinwires allowing the viewing of said lamp without obstruction.
 4. Thearrangement of claim 1, further comprising at least one sensitiveelectrical component effected by strong magnetic fields disposed withinsaid video display panel, said sensitive electrical component beinghoused within an internal metal electromagnetic shield.
 5. Thearrangement of claim 1, wherein said wire mesh is constructed from aplurality of thin wires allowing the viewing of said video imageswithout obstruction.
 6. A method of shielding a video display to preventelectromagnetic interference with a magnetic resonance imaging devicelocated in proximity to said video display, comprising the steps of:(a)positioning a patient within a magnetic resonance imaging devicedisposed in an examining room; (b) examining said patient with saidmagnetic resonance imaging device; (c) placing a video display panel insaid examining room within a magnetic field generated by a magneticresonance imaging device and within direct viewing range of saidpatient; (d) producing a video image on a video display screen withinsaid video display panel; (e) orienting said video image on said videodisplay screen in relation to an orientation of said patient within saidmagnetic resonance imaging device; (f) reflecting said video image fromsaid display screen to said patient using a mirror without a fiber opticcoupling; and (g) shielding said video display panel within a magneticshielding enclosure, said enclosure shielding said magnetic resonanceimaging device from an internal magnetic field generated by said videodisplay, and said enclosure shielding said video display panel from anexternal magnetic field generated by said magnetic resonance imagingdevice, wherein the step of shielding said video display panel comprisesthe steps of: (1) enclosing said video display in a metal box with anopen face; (2) closing said open face with by fastening a cover platewith a cut-out for a viewing screen to said metal box; (3) sealing thejoint between said metal box and said cover plate with a radio frequencyinterference gasket; and (4) covering said cut-out in said cover platewith a wire mesh.
 7. The method of claim 6, wherein the step oforienting said video image on said video display screen furthercomprises the step of:displaying said image in a normal viewingorientation when said patient is in a head-first, prone position fordirect viewing by said patient, displaying said image reversed from leftto right when said patient is in a head-first supine position, saidpatient viewing a reflection of said display screen on said mirror;displaying said image reversed from top to bottom when said patient isin a head-first supine position for direct viewing by said patient; anddisplaying said image reversed from left to right and from top to bottomwhen said patient is in a feet-first supine position viewing areflection of said display screen on said mirror.
 8. The method of claim6, wherein said step of shielding said video display panel furthercomprises the step of(5) displaying at least one viewing lamp through ahole in said cover plate; (6) covering said hole with a second wire meshmounted to said cover plate, with a brass ring, said second wire meshconstructed from thin wires allowing the viewing of said viewing lampwithout obstruction.
 9. The method of claim 6, further comprising thestep of shielding a sensitive electrical component inside said videodisplay panel with an internal electromagnetic shield.